SALT LAKE CITY — Some of world's most recognizable brands and several Utah-based businesses have come out in support of the gay and lesbian couples challenging the state's ban on same-sex marriage.

Facebook, Starbucks, Levi Strauss and popular Salt Lake City eatery Tony Caputo's Market & Deli are among 46 companies that joined together in an amicus or friend-of-the-court brief filed Tuesday in the 10th Circuit Court of Appeals.

"State laws and constitutions that deny marriage to gay and lesbian citizens are bad for our businesses," they say.

The companies argue that states like Utah that ban same-sex marriage causes them to differentiate among similarly situated employees in other places. "As a result, our ability to grow and maintain a diverse workplace is hampered, as is, in turn, our ability to grow and maintain our business," they wrote.

The brief is one of at least two dozen filed as of late Tuesday asking the appeals court to uphold U.S. District Judge Robert J. Shelby's ruling in December that stuck down Utah's voter-approved definition of marriage as between a man and a woman.

Many of those the organizations are based in Utah, including the advocacy groups Voices for Utah Children, Equality Utah and Alliance for a Better Utah, along with several religious denominations. A group of western Republicans, including two local GOP leaders, also weighed in on the case.

The briefs make a variety arguments for same-sex marriage and families from historical, psychological, sociological and legal perspectives. They describe ways in which same-sex couples and their children are harmed by Utah's marriage law known as Amendment 3.

Last week, the plaintiffs in the case argued in a court brief that the law treats same-sex couples as "legal strangers" and denies them the rights and benefits married heterosexual couples enjoy. They say the purpose of the state's voter-approved constitutional amendment is to impose inequality on same-sex couples and their children.

Utah has until March 11 to reply. Oral arguments are scheduled for April 10 in Denver.

In its appeal of Shelby's ruling, the state contends it has the constitutional authority to define marriage, and the union of a man and a woman is the best setting to bear and rear children. It also argues that traditional marriage furthers the state's interests in accommodating religious freedom and preserving social harmony in the state, while redefining marriage would be a recipe for social and religious strife.

Equality Utah and the Utah Pride Center wrote in an amicus brief that Amendment 3 has a more devastating impact on children of same-sex couples than the federal Defense of Marriage Act.

They say the law tells children, "Your parents are not really married," and, "One of your parents is not really your parent."

"Even more profoundly than DOMA, Amendment 3 ensures that children raised by same-sex couples will not be legally recognized as belonging to 'real' families —families entitled to equal respect and protection under the state’s laws," according to the brief.

Former Republican U.S. Sens. Alan Simpson of Wyoming and Nancy Kassebaum of Kansas were among 20 politicians who identified themselves "conservatives, moderates and libertarians who embrace the individual freedoms protected by our Constitution."

The group, including Salt Lake County Republican Party officials Melvin Nimer and John Storrs, says it has diverse political and social views, but embraces Ronald Reagan’s belief that the GOP must be a “big tent.”

They also share Barry Goldwater’s belief that "we don’t seek to lead anyone’s life for him. We only seek to secure his rights."

A group of religious organizations, including the Episcopal Diocese of Utah and Mormons for Equality, argue that legalizing same-sex marriage would not impinge upon religious doctrine or practice.

"All religions would remain free — as they are today with 17 states and the District of Columbia permitting same-sex couples to marry — to define religious marriage in any way they choose," according to the brief.